JP6814573B2 - Method for producing unsaturated carboxylate - Google Patents

Description

The present invention relates to a method for producing an unsaturated carboxylic acid salt using olefins and carbon dioxide as raw materials.

It is known that carbon dioxide is generated by life activities and industrial activities, and most of it is released into the atmosphere and becomes a typical causative substance of global warming. In particular, carbon dioxide generated by industrial activities is not only a serious waste but also an inexpensive C1 raw material, so there are great expectations for effective utilization technology of carbon dioxide.

Thanks to the enthusiastic research by researchers these days, many chemical conversion reactions using carbon dioxide have become known. (For example, see Non-Patent Document 1.) Among them, the reaction of synthesizing acrylate using ethylene and carbon dioxide as raw materials is attracting attention as a dream reaction of producing useful chemicals using carbon dioxide as a raw material.

Recent studies have reported that acrylates can be obtained from ethylene and carbon dioxide in nickel- and palladium-catalyzed systems. (See, for example, Patent Document 1 and Non-Patent Documents 2 and 3.) In these prior arts, the reaction proceeds through oxidative cyclization, β-hydrogen desorption, and ligand exchange. At this time, in oxidative cyclization, an extremely stable metallalactone intermediate is formed from the transition metal complex of nickel or palladium in the coexistence of ethylene and carbon dioxide, so that it is expensive to proceed with β-hydrogen desorption. It was necessary to make an excessive amount of base and Lewis acid act. Further, in Patent Document 1, the inside of the reactor had to be replaced with a high-pressure ethylene atmosphere in order to exchange the acrylate strongly π-coordinated in the ligand exchange. Furthermore, the metals used as catalysts are highly toxic nickel and expensive palladium, and it has not been easy to put them into practical use.

U.S. Pat. No. 8,697,909

T. Sakakura et al., Chem. Rev. , 2007, No. 107, pp. 2365-2387 N. Huguet et al., Chem. Euro. J. , 2014, No. 20, pp. 16858-p. 16862 S. C. E. Steiber et al., Chem. Commun. , 2015, No. 51, pp. 10907-10909

As described above, in the reaction for synthesizing acrylates using ethylene and carbon dioxide as raw materials, the prior art requires an excessive amount of expensive bases and Lewis acids, and discharges and replaces the gas in the container during the reaction. Due to the problems of using highly toxic nickel and expensive palladium, it is not feasible as an industrial process in terms of economy, safety, and environment, and it is hoped that useful processes and catalysts will be developed. It was rare.

The present invention has been made in view of the above situation, and it is not necessary to use an excessive amount of an expensive base or Lewis acid, it is not necessary to discharge or replace the gas in the container during the reaction, and highly toxic nickel or the like. It is not necessary to use expensive palladium, and it is an object of the present invention to provide an unsaturated carboxylate from olefins and carbon dioxide as raw materials.

におけるβ−水素と中心金属との相互作用が困難な配位環境のためと推測し、β−水素と中心金属との相互作用が容易な下記式（２）：

で表される５配位以上のメタララクトン種を形成しうる６族〜９族の元素に着目し、反応検討を行った。６族〜９族の元素を中心に有するメタララクトン種のβ−水素脱離では、過剰量の塩基を共存させる必要はなく、熱もしくは光といったエネルギーを与えることでβ−水素脱離が進行することを初めて明らかにした。この知見を活用して鋭意検討を重ねることで、原料ガスの置換操作も必要とせず触媒的な反応が可能になることを見出した。その結果、上記課題をみごとに解決することに想到し、本発明に到達した。 The present inventors explain the reason why β-hydrogen desorption of Group 10 elements from the planar tetracoordinated metallalactone species, which has been a problem in the prior art, does not proceed smoothly by the following equation (1):

It is presumed that this is due to the coordination environment in which the interaction between β-hydrogen and the central metal is difficult, and the interaction between β-hydrogen and the central metal is easy.

Focusing on the elements of groups 6 to 9 that can form metallalactone species with 5 or more coordinations represented by, the reaction was investigated. In β-hydrogen desorption of metallalactone species mainly containing Group 6-9 elements, it is not necessary to coexist an excessive amount of bases, and β-hydrogen desorption proceeds by applying energy such as heat or light. Was revealed for the first time. By utilizing this knowledge and conducting intensive studies, it was found that a catalytic reaction can be performed without the need for a replacement operation of the raw material gas. As a result, he came up with the idea of successfully solving the above problems, and arrived at the present invention.

That is, the present invention is a step of reacting olefins with carbon dioxide to obtain a metallalactone species in the presence of a transition metal complex containing at least one metal element selected from groups 6 to 9, and the metallalactone by β-hydrogen elimination. A method for producing an unsaturated carboxylate, which comprises a step of converting a seed into an O-carboxylate complex, and a step of regenerating a transition metal complex from the O-carboxylate complex and obtaining an unsaturated carboxylic acid. In the present invention, the metallalactone species refers to a compound having a structure in which a carbon atom in the ring is replaced with a metal.

According to the production method of the present invention, it is not necessary to use an excessive amount of expensive base or Lewis acid, it is not necessary to discharge or replace the gas in the container during the reaction, and highly toxic nickel or expensive palladium is used. It becomes possible to produce an unsaturated carboxylate from olefins and carbon dioxide as raw materials.

The present invention will be described in detail below.
In addition, a form in which two or more individual preferable forms of the present invention described below are combined is also a preferable form of the present invention.

<Details of the present invention>
The present invention is a method for producing an unsaturated carboxylic acid salt by reacting olefins with carbon dioxide in the presence of a transition metal complex, and includes the following steps.
Step of reacting olefins with carbon dioxide in the presence of a transition metal complex to obtain metallalactone species (step (I)),
A step of converting the metallalactone species into an O-carboxylate complex by β-hydrogen elimination (step (II)).
A step of regenerating a transition metal complex from the O-carboxylate complex and obtaining an unsaturated carboxylate (step (III)).

（式中、Ｒ^１〜Ｒ^３は、同一又は異なって、水素原子、フッ素原子、塩素原子又は炭素数１〜２４の有機基を表し、該Ｒ^１〜Ｒ^３の２以上はそれぞれ連結していても良い。）

（式中、Ｑ^ｎ＋は、ｎ価の陽イオンを表す。ｎは、１〜４の整数を表す。） The olefins and unsaturated carboxylates are not particularly limited, but for example, compounds represented by the following general formulas (1) and (2) are preferable.

(In the formula, R ^{1 to} R ³ represent the same or different hydrogen atom, fluorine atom, chlorine atom or organic group having 1 to 24 carbon atoms, and 2 or more of the R ^{1 to} R ³ are connected to each other. May be.)

(In the equation, Q ^{n +} represents an n-valent cation. N represents an integer of 1 to 4.)

In the above general formulas (1) and (2), R ^{1 to} R ³ represent the same or different hydrogen atom, fluorine atom, chlorine atom or organic group having 1 to 24 carbon atoms, and R ^{1 to} R ³ When 2 or more are organic groups having 1 to 24 carbon atoms, 2 or more may be linked to each other. The organic group having 1 to 24 carbon atoms is not particularly limited as long as it does not significantly inhibit the reaction, and is, for example, an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, and 6 carbon atoms. Aryl group of ~ 24, arylalkyl group of 7 to 24 carbons, alkoxy group of 1 to 24 carbons, aryloxy group of 6 to 24 carbons, alkoxycarbonyl group of 1 to 24 carbons, 7 to 24 carbons Aryloxycarbonyl group, acyl group having 1 to 24 carbon atoms, aroyl group having 7 to 24 carbon atoms, alkylsulfonyl group having 1 to 24 carbon atoms, arylsulfonyl group having 6 to 24 carbon atoms, 7 to 24 carbon atoms. Arylalkylsulfonyl group, trialkylsilyl group with 3 to 24 carbon atoms, dialkylarylsilyl group with 8 to 24 carbon atoms, alkyldiarylsilyl group with 13 to 24 carbon atoms, triarylsilyl group with 18 to 24 carbon atoms, carbon Bis (dialkylamino) phosphinoyl group having 4 to 24 carbon atoms, dialkylphosphinoyl group having 2 to 24 carbon atoms, diarylphosphinoyl group having 12 to 24 carbon atoms, dialkylphosphoryl group having 2 to 24 carbon atoms, 12 carbon atoms Examples thereof include a diarylphosphoryl group of ~ 24, a fluoroalkyl group, a trifluoromethyl group, a 4-pyridyl group, a 3-pyridyl group, a 2-pyridyl group and the like. R ^{1 to} R ³ are preferably substituents having a small bulkiness from the viewpoint of steric hindrance of the olefins described in the above general formula (1). Among them, R ^{1 to} R ³ are more preferably hydrogen atom, fluorine atom, chlorine atom, methyl group and linear alkyl group having 1 to 6 carbon atoms, further preferably hydrogen atom, fluorine atom and methyl group, and hydrogen atom is preferable. Most preferred.

One or two or more of the hydrogen atoms of the organic group having 1 to 24 carbon atoms may be substituted with a substituent, and the substituents include an alkyl group, an aryl group, an alkenyl group, an alkoxy group and an aryloxy group. Alkoxycarbonyl group, aryloxycarbonyl group, acyl group, aroyl group, alkylsulfonyl group, arylsulfonyl group, arylalkylsulfonyl group, trialkylsilyl group, dialkylarylsilyl group, triarylsilyl group, bis (dialkylamino) phosphinoyl group , Dialkylphosphinoyl group, diarylphosphinoyl group, dialkylphosphoryl group, diarylphosphoryl group, carboxyl group, sulfonyl group, amino group, silyl group, fluorine atom, chlorine atom, fluoroalkyl group, trifluoromethyl group, 4- Examples thereof include a pyridyl group, a 3-pyridyl group and a 2-pyridyl group. The carbon number of the substituent is not particularly limited as long as the organic group having the substituent has the above carbon number as a whole, but is, for example, 0 to 23.

As a form in which two or more of R ^{1 to} R ³ are connected to each other, it is exemplified that two or more selected from R ^{1 to} R ³ are integrated to form a 2-3 valent organic group. However, for example, as the divalent organic group, an alkylene group having 2 to 24 carbon atoms such as an ethylene group and a butylene group; an arylene group having 3 to 24 carbon atoms such as a phenylene group; and a carbon atom of the alkylene group and the arylene group. Examples thereof include a group in which one or more of these groups are substituted with an oxygen atom, a nitrogen atom, a sulfur atom; and a group in which one or more of the hydrogen atoms of these groups are substituted with a substituent. Examples of the substituent include groups similar to those of the organic group having 1 to 24 carbon atoms.

Examples of the n-valent cation include monovalent ammonium ions such as quaternary ammonium ion and tertiary ammonium ion; monovalent alkali metal ions such as lithium ion, sodium ion, potassium ion, rubidium ion and cesium ion; beryllium. Divalent alkaline earth metal ions such as ions, magnesium ions, calcium ions, strontium ions and barium ions; trivalent rare earth element ions such as scandium ions, yttrium ions, lantern ions and cerium ions; titanium ions, zirconium ions 2- to 4-valent transition metal ions such as vanadium ion, chromium ion, manganese ion, iron ion, cobalt ion, nickel ion, copper ion, zinc ion; trivalent typical metal ion such as aluminum ion and gallium ion. Be done. Among them, lithium ion, sodium ion, potassium ion, rubidium ion, cesium ion, and quaternary ammonium ion are preferable, and lithium ion, sodium ion, potassium ion, rubidium ion, cesium ion, and quaternary ammonium ion are more preferable. Sodium ion and potassium ion are more preferable, and sodium ion is particularly preferable.

The transition metal complex is preferably a complex composed of a metal component serving as an active site and a ligand that assists the function, and may have an anion ion. Further, the precursor of the complex and the components as a raw material may be mixed and prepared in the system.

As the metal component, those containing elements of groups 6 to 9 are preferably mentioned. Chromium, molybdenum, tungsten, manganese, renium, iron, ruthenium, cobalt, rhodium, iridium are preferred, chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt are more preferred, manganese, iron, ruthenium, cobalt are even more preferred. Ruthenium is particularly preferred.

The ligand is not particularly limited as long as it suppresses aggregation of metal components and assists or controls reactivity, but is not particularly limited, but is a monodentate nitrogen ligand such as pyridine; a monodentate phosphorus coordination such as triphenylphosphine. Child; bidentate nitrogen ligands such as 2,2'-bipyridine, N, N, N', N'-tetramethylethylenediamine; bis (diphenylphosphine) ethane, bis (diphenylphosphine) ferrocene, bis (diethyl) Bidentate phosphorus ligands such as phosphino) ethane, 1,2-bis (diethylphosphine) benzene; 2,6-bis (diphenylphosphinomethyl) pyridine, 2,6-bis (diphenylphosphinomethyl) benzene , Pincer-type tridentate ligands such as bis (diphenylphosphine ethyl) phenylphosphine; and tetradentate ligands such as tris (diphenylphosphine ethyl) phosphine. From the viewpoint of catalyst stability and reactivity, a polydentate ligand having two or more loci is preferable, a phosphorus ligand having two or more loci is more preferable, and bis (diethylphosphine) ethane and 1,2-bis (diethyl) are preferable. Phosphino) benzene, bis (diphenylphosphinoethyl) phenylphosphine, and tris (diphenylphosphinoethyl) phosphine are more preferred.

The counter anion is not particularly limited as long as it can enhance the stability of the catalyst and maintain its activity, but is a sulfonic acid ion such as trifluoromethanesulfonic acid ion, fluorosulfonic acid ion, p-toluenesulfonic acid ion; Fluorinated inorganic acid ions such as tetrafluoroborate ion, hexafluorophosphate ion, hexafluoroantimonate ion, hexafluorosilicate ion; halide ion such as chloride ion and bromide ion; oxo acid ion such as perchlorate ion; Carboxylate ions such as benzoate ion and acetate ion; alkoxide ion such as methoxydo ion; aryloxide ion; carbonate ion; hydroxide ion and the like can be preferably used. Among them, halide ion, oxoate ion, carboxylate ion, alkoxide ion, aryloxide ion, carbonate ion and hydroxide ion are more preferable, and carboxylic acid ion, alkoxide ion, aryloxide ion, carbonate ion and hydroxide ion. Is even more preferable.

（式中、Ｍ^ｎは、ｎ価の金属イオンを表す。Ｚは、任意の配位子または陰イオンまたは空の配位座を表す。Ｅは、燐原子同士を結ぶ炭素数１〜２４の架橋構造を表し、二重結合を有していても良く、単環構造又は縮環構造を有していても良く、置換基を有していても良い。Ｒ^４〜Ｒ^７は、同一又は異なって、炭素数１〜２４の有機基を表し、Ｒ^４〜Ｒ^７の２以上は、それぞれ連結していても良い。）もしくは下記一般式（４）：

（式中、Ｍ^ｎは、ｎ価の金属イオンを表す。Ｙ、Ｚは、任意の配位子または陰イオンまたは空の配位座を表す。Ｅは、燐原子同士を結ぶ炭素数１〜２４の架橋構造を表し、二重結合を有していても良く、単環構造又は縮環構造を有していても良く、置換基を有していても良い。Ｒ^８〜Ｒ^１１は、同一又は異なって、炭素数１〜２４の有機基を表し、Ｒ^８〜Ｒ^１１の２以上は、それぞれ連結していても良い。）で表される。 Among the above transition metal complexes, the complex having a bidentate phosphorus ligand is described in the following general formula (3):

(In the formula, M ⁿ represents an n-valent metal ion. Z represents an arbitrary ligand or anion or an empty coordination bond. E represents phosphorus atoms having 1 to 24 carbon atoms. It represents a crosslinked structure, may have a double bond, may have a monocyclic structure or a condensed ring structure, and may have a substituent. R ^{4 to} R ⁷ are the same or may have a substituent. Differently, it represents an organic group having 1 to 24 carbon atoms, and 2 or more of R ^{4 to} R ⁷ may be linked to each other.) Or the following general formula (4) :.

(In the formula, M ⁿ represents an n-valent metal ion. Y and Z represent arbitrary ligands or anions or empty coordination bonds. E represents 1 to 1 carbon atoms connecting phosphorus atoms. Representing the crosslinked structure of 24, it may have a double bond, a monocyclic structure or a condensed ring structure, and may have a substituent. R ^{8 to} R ¹¹ may have a substituent. The same or different, it represents an organic group having 1 to 24 carbon atoms, and 2 or more of R ^{8 to} R ¹¹ may be linked to each other).

By using the transition metal complex represented by the above general formulas (3) and (4) as a catalyst, it tends to be possible to construct a reaction system in which the catalytic activity is stably maintained, which is preferable.

Examples of the metal ion include those containing elements of groups 6 to 9. 0 to divalent chromium, molybdenum, tungsten, manganese, renium, iron, ruthenium, cobalt, rhodium, iridium are preferable, chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt are more preferable, and 0 to divalent manganese. , Iron, ruthenium, cobalt are more preferred, and zero-valent ruthenium is particularly preferred.

The above-mentioned arbitrary ligand is not particularly limited as long as it can be replaced with a reaction raw material, but is not particularly limited, but is olefins such as ethylene; sulfoxides such as dimethyl sulfoxide; amines such as triethylamine; pyridine, imidazole, thiazole, oxazole. And other heterocyclic compounds; ethers such as tetrahydrofuran; nitriles such as acetonitrile, ketones such as acetone, carbon dioxide and the like are preferably exemplified. Among them, olefins, sulfoxides, ethers, nitriles, ketones and carbon dioxide are more preferable, olefins, ethers and carbon dioxide are more preferable, and olefins are more preferable because of the ease of ligand substitution with the reaction raw material. Is particularly preferable.

The anion is not particularly limited as long as it can enhance the stability of the catalyst and maintain its activity, but is a sulfonic acid ion such as trifluoromethanesulfonic acid ion, fluorosulfonic acid ion, p-toluenesulfonic acid ion; tetra. Fluorinated inorganic acid ions such as fluoroborate ion, hexafluorophosphate ion, hexafluoroantimonate ion, hexafluorosilicate ion; halide ion such as chloride ion and bromide ion; oxo acid ion such as perchlorate ion; benzoate Carboxylate ions such as acid ion and acetate ion; alkoxide ion such as methoxydo ion; aryloxide ion; carbonate ion; hydroxide ion and the like can be preferably used. Among them, halide ion, oxoate ion, carboxylate ion, tertiary alkoxide ion, aryloxide ion, carbonate ion and hydroxide ion are more preferable, and carboxylic acid ion, tertiary alkoxide ion, aryloxide ion and hydrogen carbonate ion. , Hydroxide ions are more preferred.

In the above general formulas (3) and (4), R ^{4 to} R ¹¹ represent organic groups having 1 to 24 carbon atoms, which are the same or different, and R ^{4 to} R ¹¹ may be linked to each other. Examples of the organic group having 1 to 24 carbon atoms include an alkyl group having 1 to 24 carbon atoms, an aryl group having 6 to 24 carbon atoms, an arylalkyl group having 7 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, and a carbon number of carbon atoms. An alkoxy group having 1 to 24 carbon atoms, an aryloxy group having 6 to 24 carbon atoms, a dialkylamino group having 2 to 24 carbon atoms and the like can be preferably used. Of these, an alkyl group, an aryl group, and an arylalkyl group are preferable, and an alkyl group is more preferable. Specifically, it is particularly preferable to use a methyl group, an ethyl group, an isopropyl group, or a cyclohexyl group.

One or two or more of the hydrogen atoms of the organic group having 1 to 24 carbon atoms may be substituted with a substituent, and the substituents include an alkyl group, an aryl group, an alkenyl group, an alkoxy group, an aryloxy group and a tri. Examples thereof include an alkylsilyl group, a dialkylarylsilyl group, a triarylsilyl group, and a dialkylamino group. The carbon number of the substituent is not particularly limited as long as the organic group having the substituent has the above carbon number as a whole, but is, for example, 0 to 23.
As a form in which the two R ^{4 to} R ¹¹ are connected to each other, a form similar to the form in which two or more of the above R ^{1 to} R ³ are connected to each other is exemplified.

In the above general formulas (3) and (4), E is not particularly limited as long as it is a divalent organic group capable of connecting phosphorus atoms, but for example, it has 2 to 24 carbon atoms such as an ethylene group and a butylene group. Alkylene group; an arylene group having 3 to 24 carbon atoms such as a phenylene group; a group in which one or more carbon atoms of the alkylene group and the arylene group are substituted with an oxygen atom, a nitrogen atom and a sulfur atom; and of these groups. Examples thereof include a group in which one or more hydrogen atoms are substituted with a substituent. Examples of the substituent include groups similar to those of the organic group having 1 to 24 carbon atoms.

E may have a monocyclic structure. In other words, the crosslinked structure represented by E may include a ring structure.

When E has a monocyclic structure, the monocyclic structure and the two phosphorus atoms in the general formulas (3) and (4) may be directly bonded to each other, and the monocyclic structure and the general formulas (3) and (4) may be directly bonded to each other. ) May have a divalent substituent sandwiched between it and either phosphorus atom.
Examples of the divalent substituent include an alkylene group having 1 to 5 carbon atoms, an alkenylene group having 2 to 5 carbon atoms, a hetero atom such as an oxygen atom and a sulfur atom, or a group in which these are bonded in series. Be done.

E may have a condensed ring structure. In other words, the crosslinked structure represented by E may include a condensed ring structure.

When E has a fused ring structure, the condensed ring structure may be directly bonded to the two phosphorus atoms in the general formulas (3) and (4), and the condensed ring structure and the general formulas (3) and (4) may be directly bonded to each other. ) May have a divalent substituent sandwiched between it and either phosphorus atom.

The divalent substituent is the same as that described above as the divalent substituent sandwiched between the monocyclic structure and the two phosphorus atoms in the general formulas (3) and (4).

E may have a substituent. When E has neither a monocyclic structure nor a condensed ring structure, the substituent is a ring structure composed of E in the general formulas (3) and (4), a phosphorus atom, and ^Mn. It is a substituent of the part E in the inside. When E has a monocyclic structure or a fused ring structure, the substituent is a substituent having a monocyclic structure or a condensed ring structure, or other E and two phosphorus in the general formulas (3) and (4). It is a substituent of the E portion in the ring structure composed of an atom and M ⁿ .

The substituent may have, for example, a hetero atom, or may be another atom or atomic group. Examples of the substituent having the hetero atom include an alkoxy group having 1 to 18 carbon atoms, an arylalkoxy group having 7 to 18 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, an acyl group having 2 to 18 carbon atoms, and a carbon number of carbon atoms. Examples thereof include an aloyl group of 7 to 18, a dialkylamino group having 2 to 18 carbon atoms, an oxygen atom and a sulfur atom. Examples of the other atom or atomic group include an aryl group having 6 to 18 carbon atoms, an alkyl group having 1 to 18 carbon atoms, a halogen atom and the like.

The carbon number of E is preferably 12 or less, more preferably 10 or less, and even more preferably 8 or less. Further, the carbon number of E is preferably 2 or more. It is particularly preferable that E has an ethylene, 1,2-phenylene structure.

（式中、Ｍ^ｎは、ｎ価の金属イオンを表す。Ｙ、Ｚは、任意の配位子または１価の陰イオンまたは空の配位座を表す。Ｅは、燐原子同士を結ぶ炭素数１〜２４の架橋構造を表し、二重結合を有していても良く、単環構造又は縮環構造を有していても良く、置換基を有していても良い。Ｒ^１２〜Ｒ^１４は、同一又は異なって、炭素数１〜２４の有機基を表し、Ｒ^１２〜Ｒ^１４の２以上は、それぞれ連結していても良い。）で表される錯体である場合も、本発明の特に好ましい形態のひとつである。 The transition metal complex has the following general formula (5):

(In the formula, M ⁿ represents an n-valent metal ion. Y and Z represent an arbitrary ligand or a monovalent anion or an empty coordination bond. E represents a carbon connecting phosphorus atoms to each other. It represents a crosslinked structure of the number 1 to 24, may have a double bond, may have a monocyclic structure or a condensed ring structure, and may have a substituent. R ^{12 to} R ¹⁴ represents the same or different organic group having 1 to 24 carbon atoms, and 2 or more of R ^{12 to} R ¹⁴ may be linked to each other). Is one of the particularly preferable forms of.

（式中、Ｍ^ｎは、ｎ価の金属イオンを表す。Ｘ、Ｙ、Ｚは、任意の配位子または１価の陰イオンまたは空の配位座を表す。Ｌは、燐原子同士を結ぶ炭素数１〜２４の架橋構造を表し、二重結合を有していても良く、単環構造又は縮環構造を有していても良く、置換基を有していても良い。Ｒ^１５〜Ｒ^１７は、同一又は異なって、炭素数１〜２４の有機基を表し、Ｒ^１５〜Ｒ^１７の２以上は、それぞれ連結していても良い。）で表される錯体である場合も、本発明の特に好ましい形態のひとつである。 The transition metal complex has the following general formula (6):

(In the formula, M ⁿ represents an n-valent metal ion. X, Y, Z represent an arbitrary ligand or a monovalent anion or an empty coordination bond. L represents phosphorus atoms. It represents a crosslinked structure having 1 to 24 carbon atoms to be connected, may have a double bond, may have a monocyclic structure or a condensed ring structure, and may have a substituent. R ¹⁵ ~ R ¹⁷ represents the same or different organic groups having 1 to 24 carbon atoms, and 2 or more of R ^{15 to} R ¹⁷ may be linked to each other). It is one of the particularly preferable forms of the present invention.

As a method for producing the transition metal complex represented by the general formulas (3) to (6), a known method can be used. For example, the simplest method is to add a desired ligand to a low valence complex coordinated with olefins and stir in a solution to exchange the ligand. A method of stirring a transition metal complex having a trimethylphosphine ligand and a desired polydentate phosphorus ligand in a solution is also used. If necessary, it can be reduced to a low valence complex using a reducing agent.

Each step of the manufacturing method of the present invention can be selected from a batch type, a distribution type and the like according to the purpose. In the case of a batch type reaction, the reaction time can be set as appropriate, but for example, it is preferably 5 minutes or longer, more preferably 15 minutes or longer, and even more preferably 30 minutes or longer. The reaction time is preferably as short as possible within the range of reaching the target reaction rate, and is preferably 100 hours or less, for example.

A solvent can be used in each step of the production method of the present invention. The reaction solvent can be appropriately adopted, and for example, water; alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; aromatic or aliphatic hydrocarbons such as benzene, toluene, xylene, cyclohexane and n-hexane; acetic acid. Estel compounds such as ethyl; ketone compounds such as acetone and methyl ethyl ketone; cyclic ether compounds such as tetrahydrofuran and dioxane; chain ether compounds such as dibutyl ether and diisopropyl ether; dichloromethane, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1 , 1,1-Trichloroethane, 1,1,2,2-tetrachloroethane, 1,2-dichloroethylene, trichloroethylene, tetrachloroethylene and other halogenated hydrocarbons; dimethylsulfoxide and other sulfoxides; N, N-dimethylformamide, N -Amids such as methylpyrrolidone; ureas such as tetramethylurea, N, N'-dimethylimidazolidinone and the like, and one or more of these can be used. The reaction solvent is preferably aromatic or aliphatic hydrocarbons, cyclic ether compounds, chain ether compounds, halogenated hydrocarbons, sulfoxides, amides, ureas and water, and cyclic ether compounds and halogenated hydrocarbons. , Sulfoxides, amides, ureas and water are more preferred, and cyclic ether compounds, sulfoxides, amides and ureas are even more preferred. It is particularly preferable to use tetrahydrofuran, N, N-dimethylformamide as the reaction solvent.

The production method of the present invention, particularly step (I), is usually carried out under the pressure of olefins and / or carbon dioxide (preferably carbon dioxide). From the viewpoint of the reaction rate, the total pressure of the olefins and / or carbon dioxide is preferably 0.1 atm or more, more preferably 1 atm or more, and further preferably 10 atm or more. Further, from the viewpoint of safety, the pressure is preferably 500 atm or less, and more preferably 200 atm or less.

In each step of the production method of the present invention, the reaction temperature can be appropriately selected depending on the type of catalyst, but in order to obtain a sufficiently high reaction rate, it is preferably 0 ° C. or higher, preferably 40 ° C. or higher. It is more preferably 80 degrees or more, and particularly preferably 100 degrees to 140 degrees.

The molar ratio of carbon dioxide to the olefins represented by the general formula (1), which is the raw material in the present invention, is preferably 1/10 to 10/1, more preferably 1/5 to 5/1, and 1 / 2 to 2/1 is more preferable, 1 / 1.5 to 1.5 / 1 is more preferable, and 1/1 is particularly preferable.

In the production method of the present invention, steps (I) to (III) may be carried out in one pot or in sequence. When a part or all of each of the steps (I) to (III) is performed separately, a purification step or the like may be provided between any of the steps. A method in which steps (I) to (III) are simultaneously performed in one pot is particularly preferable.

（式中、Ｍ^ｎは、ｎ価の金属イオンを表し、Ｍ^ｎ＋２は、ｎ＋２価の金属イオンを表す。ｎは０〜２の整数を表す。Ｌは配位子または対陰イオンまたは空の配位座を表し、同一または異なっていても良い。）
工程（ＩＩ）：

（式中、Ｍ^ｎ＋２は、ｎ＋２価の金属イオンを表す。ｎは０〜２の整数を表す。Ｌは配位子または対陰イオンまたは空の配位座を表し、同一または異なっていても良い。）
工程（ＩＩＩ）：

（式中、Ｍ^ｎは、ｎ価の金属イオンを表し、Ｍ^ｎ＋２は、ｎ＋２価の金属イオンを表す。ｎは０〜２の整数を表す。Ｌは配位子または対陰イオンまたは空の配位座を表し、同一または異なっていても良い。Ｑ^ｎ＋は、ｎ価の陽イオンを表す。ｎは、１〜４の整数を表す。） Specific examples of the reaction formulas of the above steps (I) to (III) are shown below when the olefins are ethylene.
Step (I):

(In the formula, M ⁿ represents an n-valent metal ion, M ^{n + 2} represents an n + divalent metal ion. N represents an integer of 0 to 2. L represents a ligand or an anion or empty. Represents a coordination position and may be the same or different.)
Step (II):

(In the equation, M ^{n + 2} represents an n + divalent metal ion. N represents an integer from 0 to 2. L represents a ligand or an anion or an empty coordination bond, even if they are the same or different. good.)
Step (III):

(In the formula, M ⁿ represents an n-valent metal ion, M ^{n + 2} represents an n + divalent metal ion. N represents an integer of 0 to 2. L represents a ligand or an anion or empty. It represents a coordination constellation and may be the same or different. Q ^{n +} represents an n-valent cation. N represents an integer of 1 to 4).

The production method of the present invention may include the above steps (I) to (III) (hereinafter, collectively referred to as "reaction step"), and may be any other optional step such as purification step, extraction step, drying step and the like. The steps may be included, but may include, for example, the step of obtaining the carboxylic acid by an appropriate method such as neutralization, dialysis, membrane separation, etc. using the carboxylate obtained in the reaction step.

The acid-type unsaturated carboxylic acid is produced, for example, including a step (neutralization step) of adding an acid to a composition containing an acid-type unsaturated carboxylic acid salt or an unsaturated carboxylic acid salt to acidify the pH. To. The salt or the like produced at this time may be separated or removed by filtration, dialysis, membrane separation or the like.

Further, in the step of producing the acid type unsaturated carboxylic acid, in order to isolate the acid type unsaturated carboxylic acid, an organic solvent is added to the composition containing the acid type unsaturated carboxylic acid to form the acid type. It may include a step of precipitating or extracting the unsaturated carboxylic acid of.

The above steps can be combined or repeated as necessary.

In the above neutralization step, the acid may be either a mineral acid or an organic acid, and examples thereof include hydrochloric acid, sulfuric acid, nitric acid, sulfite, phosphoric acid, boric acid, carbonic acid, acetic acid, citric acid and the like, but they are inexpensive. From the aspect, it is preferable to use hydrochloric acid or sulfuric acid. Further, in the neutralization step, setting the pH to less than 2 is preferable because the production efficiency is increased. More preferably, the pH is about 1.

The amount of acid added in the neutralization step is preferably at least this molar amount, preferably 1.3 times the amount of the carboxyl group.
After producing an acid-type unsaturated carboxylic acid, it may be distilled, dried and solidified.

The carboxylic acid salt and carboxylic acid obtained by the production method of the present invention are also one of the present inventions.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
Various measurements and evaluations were performed by the following methods.

Liquid NMR ( ¹ H-NMR, ¹³ C-NMR, and ³¹ P-NMR) measurements were performed using JEOL ECX-500, JEOL ECX-400, JEOL ECZ-500, Bruker DRX-500, and ¹ H. -NMR was measured at 500 MHz or 400 MHz. ¹³ C-NMR was measured at 125 MHz. ³¹ P-NMR was measured at 202.5 MHz.

ESI-MS was measured using SHIMADZU LCMS-2020.

IR was measured using JASCO FT / IR-460 plus ATR PRO450-S accessory.

GC was measured using SHIMADSU GC-2010 equipped with DB-WAXETR volume.

UV irradiation was performed using USHIO Optical Modulex OPM2-502XQ with a cold filter SC0451 (Asahi Spectra Co., Ltd.) and a band pass filter LX0365 (Asahi Spec.).

The X-ray structure analysis was carried out using Rigaku R-AXIS Varimax RAPID-II with IP area detector system CuKα diffraction, Rigaku Saturn 724+ (4x4 bin mode) using MoKα diffraction.

アルゴン雰囲気下、ジクロロテトラキス（ジメチルスルホキシド）ルテニウム（ＩＩ）：錯体Ａと２当量のビス（ジエチルホスフィノ）エタンを量り採り、トルエンを添加して１００度で７時間撹拌した後、徐々に室温まで冷却した。溶媒を減圧留去するとビス［ビス（ジエチルホスフィノ）エタン］ルテニウム（ＩＩ）ジクロリド：錯体Ｂが得られた。^１Ｈ−ＮＭＲ、^１３Ｃ−ＮＭＲ、及び、^３１Ｐ−ＮＭＲを測定し、錯体Ｂの生成を確認した。アルゴン雰囲気下、錯体ＢをＴＨＦに溶解し、エチレン雰囲気下、ナトリウムを添加した。室温で３日間撹拌した後溶媒を減圧留去し、得られた固体をペンタンで洗浄した後に減圧下にて脱溶媒を行うとビス［ビス（ジエチルホスフィノ）エタン］エチレンルテニウム（０）：錯体Ｃが得られた。^１Ｈ−ＮＭＲ、^１３Ｃ−ＮＭＲ、及び、^３１Ｐ−ＮＭＲを測定し、またＸ線結晶構造解析により錯体Ｃの生成を確認した。
前述の合成例により錯体Ｆとして、下記一般式（３）：

（式中、Ｍ^ｎは、ｎ価の金属イオンを表す。Ｚは、任意の配位子または１価の陰イオンを表す。Ｅは、燐原子同士を結ぶ炭素数１〜２４の架橋構造を表し、二重結合を有していても良く、単環構造又は縮環構造を有していても良く、置換基を有していても良い。Ｒ^４〜Ｒ^７は、同一又は異なって、炭素数１〜２４の有機基を表し、Ｒ^４〜Ｒ^７の２以上は、それぞれ連結していても良い。）で表される錯体のうち、Ｍ^ｎとして０価のルテニウムを、Ｚとしてエチレンを、Ｅとしてエチレンを、Ｒ^４〜Ｒ^７としてエチル基を有する錯体を示したが、その他の錯体についても同様の方法により合成することができ、下記一般式（４）：

（式中、Ｍ^ｎは、ｎ価の金属イオンを表す。Ｙ、Ｚは、任意の配位子または１価の陰イオンを表す。Ｅは、燐原子同士を結ぶ炭素数１〜２４の架橋構造を表し、二重結合を有していても良く、単環構造又は縮環構造を有していても良く、置換基を有していても良い。Ｒ^８〜Ｒ^１１は、同一又は異なって、炭素数１〜２４の有機基を表し、Ｒ^８〜Ｒ^１１の２以上は、それぞれ連結していても良い。）で表される錯体についても同様の方法により合成することができる。 <Example 1>
[Example of Synthesis of Catalyst of the Present Invention]

Under an argon atmosphere, weigh dichlorotetrakis (dimethyl sulfoxide) ruthenium (II): complex A and 2 equivalents of bis (diethylphosphino) ethane, add toluene, stir at 100 ° C. for 7 hours, and then gradually bring to room temperature. Cooled. When the solvent was distilled off under reduced pressure, bis [bis (diethylphosphino) ethane] ruthenium (II) dichloride: complex B was obtained. ^{1 1} H-NMR, ¹³ C-NMR, and ³¹ P-NMR were measured, and the formation of complex B was confirmed. Complex B was dissolved in THF under an argon atmosphere, and sodium was added under an ethylene atmosphere. After stirring at room temperature for 3 days, the solvent was distilled off under reduced pressure, the obtained solid was washed with pentane, and then the solvent was removed under reduced pressure. Bis [bis (diethylphosphino) ethane] ethylene ruthenium (0): complex C was obtained. ^{1 1} H-NMR, ¹³ C-NMR, and ³¹ P-NMR were measured, and the formation of complex C was confirmed by X-ray crystal structure analysis.
According to the above synthesis example, the complex F is represented by the following general formula (3):

(In the formula, M ⁿ represents an n-valent metal ion. Z represents an arbitrary ligand or a monovalent anion. E represents a bridge structure having 1 to 24 carbon atoms connecting phosphorus atoms. Represented, it may have a double bond, a monocyclic structure or a condensed ring structure, and may have a substituent. R ^{4 to} R ⁷ are the same or different. represents an organic group having 1 to 24 carbon ^atoms, 2 or more R 4 to R ^7, among the complexes represented by each may be linked.), a zero-valent ruthenium as ^{M n,} ethylene as Z A complex having an ethyl group as E and an ethyl group as R ^{4 to} R ⁷ was shown, but other complexes can also be synthesized by the same method, and the following general formula (4):

(In the formula, M ⁿ represents an n-valent metal ion. Y and Z represent an arbitrary ligand or a monovalent anion. E represents a bridge having 1 to 24 carbon atoms connecting phosphorus atoms. It represents a structure, may have a double bond, may have a monocyclic structure or a condensed ring structure, and may have a substituent. R ^{8 to} R ¹¹ are the same or different. Therefore, a complex represented by an organic group having 1 to 24 carbon atoms and 2 or more of R ^{8 to} R ¹¹ may be linked to each other can also be synthesized by the same method.

アルゴン雰囲気下、錯体Ｃ（５μｍｏｌ）にＮ，Ｎ−ジメチルアセトアミド（ＤＭＡ）（０．５ｍｌ）を添加し、エチレンおよび二酸化炭素を封入し、６０℃にて２時間加熱すると収率８８％で錯体Ｄが生成した。^３１Ｐ−ＮＭＲを測定し、内部標準物質：亜燐酸トリフェニルとの比から、錯体Ｄの収率を求めた。^１Ｈ−ＮＭＲ、^１３Ｃ−ＮＭＲ、及び、^３１Ｐ−ＮＭＲ、ＩＲ、ＥＳＩ−ＭＳを測定し、またＸ線結晶構造解析により錯体Ｄの生成を確認した。 <Example 2>
[Example of elementary reaction of the present invention: oxidative cyclization]

Under an argon atmosphere, N, N-dimethylacetamide (DMA) (0.5 ml) was added to the complex C (5 μmol), ethylene and carbon dioxide were sealed, and the complex was heated at 60 ° C. for 2 hours to obtain a complex with a yield of 88%. D was generated. ³¹ P-NMR was measured, and the yield of complex D was determined from the ratio of the internal standard substance: triphenyl phosphite. ^{1 1} H-NMR, ¹³ C-NMR, and ³¹ P-NMR, IR, ESI-MS were measured, and the formation of complex D was confirmed by X-ray crystal structure analysis.

アルゴン雰囲気下、錯体Ｄ（２．５μｍｏｌ）にＤＭＡ（０．５ｍｌ）を添加し、１００℃にて２時間加熱すると収率３４％で錯体Ｅが生成した。^３１Ｐ−ＮＭＲを測定し、錯体Ｅの収率を求めた。 <Example 3>
[Example of elementary reaction of the present invention: β-hydrogen desorption by heating]

DMA (0.5 ml) was added to complex D (2.5 μmol) under an argon atmosphere, and heating was performed at 100 ° C. for 2 hours to form complex E in a yield of 34%. ³¹ P-NMR was measured to determine the yield of complex E.

アルゴン雰囲気下、錯体Ｄ（２．５μｍｏｌ）にＤＭＡ（０．５ｍｌ）を添加し、０℃にて１０時間３６５ｎｍの光を照射すると収率１００％で錯体Ｅが生成した。^３１Ｐ−ＮＭＲを測定し、錯体Ｅの収率を求めた。 <Example 4>
[Example of elementary reaction of the present invention: β-hydrogen desorption by light irradiation]

DMA (0.5 ml) was added to complex D (2.5 μmol) under an argon atmosphere, and irradiation with light at 365 nm for 10 hours at 0 ° C. produced complex E in a yield of 100%. ³¹ P-NMR was measured to determine the yield of complex E.

アルゴン雰囲気下、錯体Ｆ（２．５μｍｏｌ）とナトリウム２−フルオロ−フェノキシド（６２．５μｍｏｌ）にＤＭＡ（２ｍｌ）を添加し、エチレン、二酸化炭素加圧条件下１４０℃にて６時間加熱攪拌したのち、塩酸で処理するとアクリル酸（９．２５μｍｏｌ）が得られた。ＧＣを測定し、内部標準物質との比から、アクリル酸の収率を求めた。 <Example 5>
[Catalyst reaction example 1 of the present invention]

DMA (2 ml) was added to the complex F (2.5 μmol) and sodium 2-fluoro-phenoxide (62.5 μmol) under an argon atmosphere, and the mixture was heated and stirred at 140 ° C. under pressurized conditions of ethylene and carbon dioxide for 6 hours. Acrylic acid (9.25 μmol) was obtained by treatment with hydrochloric acid. The GC was measured and the yield of acrylic acid was determined from the ratio with the internal standard substance.

アルゴン雰囲気下、錯体Ｇ（１０μｍｏｌ）と炭酸ナトリウム（２５０μｍｏｌ）とナトリウム２，６−ジ（ｔ−ブチル）−４−メチル−フェノキシド（２５０μｍｏｌ）にＤＭＡ（２ｍｌ）を添加し、エチレン、二酸化炭素加圧条件下１４０℃にて６時間加熱攪拌したのち、塩酸で処理するとアクリル酸（１５μｍｏｌ）が得られた。ＧＣを測定し、内部標準物質との比から、アクリル酸の収率を求めた。 <Example 6>
[Catalyst reaction example 2 of the present invention]

Under an argon atmosphere, DMA (2 ml) was added to the complex G (10 μmol), sodium carbonate (250 μmol), sodium 2,6-di (t-butyl) -4-methyl-phenoxide (250 μmol), and ethylene and carbon dioxide were added. Acrylic acid (15 μmol) was obtained by heating and stirring at 140 ° C. for 6 hours under pressure conditions and then treating with hydrochloric acid. The GC was measured and the yield of acrylic acid was determined from the ratio with the internal standard substance.

As described above, according to the production method of the present invention, no expensive base or Lewis acid is used, no gas discharge or replacement in the container is required during the reaction, and highly toxic nickel or expensive. It becomes possible to provide an unsaturated carboxylate from olefins and carbon dioxide as raw materials without using palladium.

Claims (3)

At least one look-containing metal element selected from Group 9 from Group 6, a transition metal complex or bidentate multidentate ligand is more coordinating or the tridentate or higher multidentate ligand has one coordinated The process of reacting olefins with carbon dioxide in the presence of
A step of converting the metallalactone species into an O-carboxylate complex by β-hydrogen elimination,
A method for producing an unsaturated carboxylic acid salt, which comprises a step of regenerating a transition metal complex from the O-carboxylate complex and obtaining an unsaturated carboxylic acid salt. Look containing ruthenium, the reaction of olefins and carbon dioxide to bidentate or multidentate ligand is more coordinating or tridentate or higher multidentate ligands in the presence of a transition metal complex obtained by one coordinated A method for producing an unsaturated carboxylate, which comprises allowing the mixture to grow. A method for producing an unsaturated carboxylic acid, which comprises a step of neutralizing the unsaturated carboxylic acid salt according to claim 1 or 2 and / or a step of dialyzing and / or a step of membrane separation.